... psychiatrist's supervision because of the excessive sleepiness and vomiting every night. Last Sunday 6/6 was his last day on it. He is still waking up every night at 1:00 with excessive acid that causes him to vomit. Does anyone have any idea how long this after-effect might last? Also I read that Clozaril may be a cause of colitis; I am concerned about this possibility. Thank you to anyone who has any knowledge or experience with this side effect (the vomiting).